Incidence and microbiology of abdominal and pelvic abscess in Crohn's disease.

The incidence of abdominal and pelvic abscess is reported from a consecutive series of 111 patients undergoing 124 resections for Crohn's disease. Preoperative abscesses were found as a complication of Crohn's disease in 13 patients (10%) and 8 were clinically unsuspected. The majority of preoperative abscesses were confined to one site (localized to bowel, psoas sheath, pelvis, or in the abdominal wall). All preoperative abscesses occurred in patients requiring an emergency or urgent operation. Patients with a preoperative abscess had significantly lower serum albumin levels and significantly increased serum alkaline phosphatase values than the patients without an abscess. Postoperative abscesses occurred in 17 patients (14%) and six were multiple. Five of the postoperative abscesses occurred in patients who had had a preoperative abscess; these recurrent abscesses all presented 6-14 wk after an uncomplicated initial operation. The principal bacterial isolates were Escherichia coli (54%), Bacteroides fragilis (44%), enterococci (41%), and viridans streptococci (31%). The incidence of abscess was unrelated to the use of preoperative steroid therapy.